1. Field of the Invention
This invention relates to tris(disubstituted amino)sulfonium perfluorocarbanion salts and to process for the preparation thereof, the carbanion salts being useful as polymerization catalysts and as reagents for preparing fluoro-organic compounds.
2. Background
Tris(dialkylamino)sulfonium (TAS) salts of the formula
(R.sup.1 R.sup.2 N)(R.sup.3 R.sup.4 N)(R.sup.5 R.sup.6 N)S.sup..sym. X.sup..crclbar. wherein each R is C.sub.1-20 alkyl having at least two .alpha.-hydrogen atoms and X is (CH.sub.3).sub.3 SiF.sub.2, Cl, Br, I, CN, NCO, NCS, NO.sub.2 or N.sub.3 are disclosed in U.S. Pat. No. 3,940,402. The TAS salts are soluble in organic liquids and are useful as polymerization catalysts and as reagents for replacing various groups in organic compounds with the group X.
Chambers et al., J.C.S. Perkin I, 1980, 435-439, disclose the preparation of fluorocarbanions by reacting CsF and selected fluoroolefins in dimethylformamide (DMF), the olefins being perfluorocycloalkene derivatives. The product anions are observed by .sup.19 F NMR spectroscopy and are trapped with bromine or chlorine to give bromo- or chloro-fluorocycloalkanes.
The preparation of solutions of N,N,N'N'-tetramethylformamidinium perfluorocarbanions in DMF by reacting [(CH.sub.3).sub.2 N].sub.2 C.sup..sym. HF.sub.2.sup..crclbar. and branched perfluoroolefins is disclosed by Delyagina et al., Izv. Akad. Nauk SSSR, Ser. Khim., No. 10, 2238-2243 (1981), English language translation. The carbanions are characterized in solution by .sup.19 F NMR spectroscopy and found to be stable at low temperature.
Young, Fluorine Chem. Rev., 1967, 1, 359-397, particularly pages 360-336, 371-377 and 383-387, reviews perfluoroalkyl carbanion chemistry, in general, and the dimerization and polymerization of olefins, in particular. The use of fluorocarbanions in nucleophilic displacements, particularly for fluoroalkyl iodide synthesis, is discussed in detail.
Brunskill et al., Chem. Communications, 1970, 1444-1446, disclose the fluoride ion-catalyzed oligomerization (dimerization and trimerization) of hexafluoropropene and the formation of heptafluoroisopropyl carbanion.